Plug-in or extended range hybrid electric vehicles may include one or more electric traction drive motors powered by an engine-driven generator and/or storage battery. Extended range electric vehicles should include sufficient electrical energy storage to provide full vehicle driving performance for a desired time or distance without operating the internal combustion engine. If a hybrid vehicle is operated solely from the energy stored within the storage battery or similar device, it should be quiet and should not consume fuel or emit exhaust. After the electrical energy stored in the battery is consumed, the hybrid vehicle may continue operation with the support of the power generated by the internal combustion engine. However, the operator may have little or no control or information about the choice of energy sources or the rate at which each energy source is depleted.
A user interface for energy sources on such a hybrid vehicle is needed that will provide information on the amount of energy available from both a battery pack and a liquid fuel tank, and allow the operator to select when and how much stored energy is used from each energy source.